Need advice on exhaust
 

I currently have a 13B 4 port street ported engine that is going into a 1973 RX2.
I am using a road race header and I also have a PRIMA FLOW muffler for an 1984 GSL-SE. What set up should I use? Should I go with a single 2" pipe, or single 2.5"pipe or single 3" inch pipe to the muffler. Or better yet should I go Dual pipes 2"-2.5" or 3" pipe to an unflanged collector to connect with the muffler. I am open for suggestions.

Any ideas